Ronstadt says she began showing the symptoms of Parkinson's up to eight years ago but was only recently diagnosed with the disease in January.

"I couldn't sing and I couldn't figure out why," the 67-year-old rock/pop singer told the AARP. "I knew it was mechanical. I knew it had to do with the muscles, but I thought it might have also had something to do with the tick disease that I had. And it didn't occur to me to go to a neurologist.

"I think I've had it for seven or eight years already, because of the symptoms that I've had. Then I had a shoulder operation, so I thought that's why my hands were trembling. Parkinson's is very hard to diagnose, so when I finally went to a neurologist and he said, 'Oh, you have Parkinson's disease,' I was completely shocked. I wouldn't have suspected that in a million, billion years."